I went on a mission trip to Uganda back in May '13 and took a number of pictures in order to report back to my home church regarding my trip.

I found that it was difficult to get the right exposure when I as a Caucasian was standing next to a Ugandan. One of us was over/under exposed.

I will be shooting two other events locally where those in attendance will be predominantly African American and I am hoping that you all will be able to give me some advice on metering for proper exposure.

It is what it is. Photography is capturing the reflection of light. Darker skin reflects light considerably differently than lighter skin. Put the two of them together, and you get some lighting challenges. I sometimes shoot biracial couples' weddings, so I occasionally get to deal with this fun challenge.

The way I've handled it -- and it's certainly not the only way, or necessarily the best way -- is to expose for the lighter skin. I prefer not to have blown highlights. I can always edit back in the darker skin. It's not much, but I hope it helps some.

Take an incident or flash meter reading and work off that in manual. As fris said, you can then
touch up the skin exposure on one or the other, but better to lift the darker areas than loose highlights.
Cheers

No, you don't spot meter on their faces, you hold the meter in front of them, but facing toward you and take an incident reading of the light falling on them. If you spot meter a black persons face, it will try to make the exposure come out as neutral gray whether they are very black or a light shade of black.

The flash automatically controls the exposure. If you are using a digital camera, you can change the flash by the flash compensation button after looking at the back LCD to make the image look right. Most cameras have a compensation button for regular and flash compensation. I don't remember if you said what camera you were using.

@ldrussell, Life and photography is full of trade offs. It appears the trade off you're willing to make is expose you well in the images and not the people whom you are visiting. Based on my limited knowledge of missions I would think this would lead you to a goal that would expose for your hosts. No? You can always doge and burn too.

You could also take two pictures of each pose. One exposing for the white person and one exposing for the black people. That would satisfy everyone. Someone may have already mentioned this solution already.

I've photographed weddings and engagements with black and white people and never had problems accurately portraying them. Now that I think about it, no white person is whiter than a wedding dress and I've never had problems keeping detail in the dress unless I was in direct sunlight in the middle of the day, but then the same problem would show up with a white bride. The most important thing is to find soft or indirect lighting.